1. Field of the Invention
The present invention relates to a polarizing complex with functional layers, in particular a polarizing complex having a polarizing plate with lower retardation value and functional layers laminated thereon.
Specifically, the present invention discloses a polarizing plate with a protecting layer of polycarbonate having lower retardation value and a polarizing complex including the polarizing plate and suitable layer(s) laminated thereon considering the use of the polarizing complex.
2. Description of the Background Art
In general, a polarizing plate may be utilized for manufacturing glasses, a goggle, a window blind, a sun-visor for a car and a LCD displays. The polarizing plate of the present invention may be preferably used for manufacturing glasses or the goggle. The polarizing plate may be generally used for anti-glare, and the polarizing plate may comprise a protecting layer or various functional layers. A method for producing a polarizing film included into the polarizing plate is known in this art, and for example the polarizing film may be manufactured by elongating poly vinyl alcohol (PVA) or poly ethylene terephthalate (PET) along an axe after dye, or absorption of iodine or a dichromatic color.
The known materials for use of the protecting layer may be in the form of resin sheet or film and the resin sheet may comprise tri-acetyl cellulose, acrylic resins, poly esters, poly amides, poly urethanes or poly carbonates. In particular, poly carbonate is preferable for use of optical wares such as glasses, goggles and sun-glasses because poly carbonate have excellent flexibility and workability as well as excellent impact resistance, thermal resistance, wear resistance and transparency. However, compared to other transparent materials, polycarbonate is known as having some problem with the polarized light owing to the color interference fringe or optical distortion which may cause asthenopia of eye or a headache even though it has no problem with ordinary light.
Furthermore, a curve-machining development for lens structure may cause the color interference to increase. And also it is known that poly carbonate with high retardation value may have poor solvent resistance in the adhesion process resulting to cracking phenomenon after manufacturing. Hence it may be difficult to obtain a polarizing plate with uniform surface.
U.S. Pat. No. 5,051,309 entitled as “Anti-Dazzling Polycarbonate Polarizing Plate” discloses a polarizing plate using poly carbonate as a protecting layer of a polarizing film. The above invention utilizes a poly carbonate sheet as protecting layer instead of tri-acetyl cellulose sheet, acrylic sheet, poly ester sheet, poly amide sheet or poly urethane sheet. The color interference fringe from the poly carbonate sheet can be diminished by using a poly carbonate sheet with retardation value more than 2000 nm. And also the polarizing plate of the above invention is treated with boric acid in the presence of metal to enhance the polarization and durability.
As prior art relating to a polarizing plate, JP publication No. 95503/1984 suggests a method that a film of poly vinyl alcohol is dyed bi-chromatic color and then treats it with boric acid after elongation and heat-treatment under tension.
No prior invention discloses a method that a polarizing film of poly vinyl alcohol is produced in the absence of metal ions and then a protecting film of poly carbonate with lower retardation value may be laminated thereon as a protecting layer.
Therefore the present invention discloses a polarizing plate that no metal ion is used in the manufacturing process and a poly carbonate sheet with retardation as much as 10 nm is laminated on a polarizing film of poly vinyl alcohol sheet.
On the other hand a polarizing complex is a material comprising a polarizing plate and functional layers laminated on the polarizing plate, and may be used for manufacturing glasses or a goggle.
As a conventional invention relating to the complex, US publication No. 2002/84023 entitled as “A polarizing compact and a method for producing the same” describes a polarizing complex for overcoming disadvantage of the known invention. The purpose of the above invention is to resolve the problem that a polarizing glass lens sheet whose both sides are coated with glass is devoid of workability and the capability of polarization can decrease on casting the polarizing plastic lens owing to contraction of the polarizing film sheet and heat decomposition. The above invention coats at least one surface of the polarizing compact with at least one functional surface machining film for enhancing the functionality.
In addition, U.S. Pat. No. 5,871,614 entitled as “Production of Optical Elements” discloses a polarizing complex. The above invention is characterized in that a first thermoplastic resin sheet is fixed on a power portion and then functional portions are laminated thereon. The functional portions may have optical properties relating to photochromism, polarization, hardness, ware resistance, chemical resistance, color shadow, coloration, adornment, index and the like.
No known invention disclose advantage of a protecting layer or sheet having peculiar optical property. The protecting layer with peculiar optical property may enhance the functionality of the polarizing complex. The polarizing complex may comprise various functional layers and it is possible to take advantages such as improvement of a desired property, the simplicity of the manufacturing process and the lower expense for producing by using special layers with peculiar optical properties.